Bianca Censori Struts Through Town in Tight Outfit With Sister and Mom

Bianca Censori is hitting the town back home in Australia ... and wearing one of her most eye-popping outfits yet.

The Aussie bombshell stepped out for a high-end shopping spree in Melbourne with her mom, Alexandra, sister, Angelina, and other family members Monday.

Her outfit is a total head-turner ... rocking a pair of sheer tights with her underwear visibly showing -- paired with a pink tank top pulled down to reveal a pointed, purple, vintage-style bullet bra. She finished the look with silver heels.

Bianca sticks out like a sore thumb next to her relatives ... with her bright-colored outfit popping against their darker outfits.

Her mom and sis are keeping things more low-key ... Alexandra is seen in an all-black 'fit, while Angelina opts for a black tank and a fresh pair of jeans.

The crew looks like they're having a ball during their high-end shopping excursion ... which included a stop at a ritzy cosmetic shop.